Various arrangements of animal feeder are provided in which there is a trough into which feed can be deposited from a hopper above the trough. In most cases the feed material to be deposited can vary in particle size and viscosity so that it is often desirable to provide an arrangement which allows an adjustment of the opening through which the material can feed from the hopper into the trough.
In many cases the opening is provided by a simple shutter at the gap between the Hopper and the trough where the height of the shutter can be adjusted to vary the gap at the bottom of the shutter.
In U.S. Pat. No. 4,660,508 (Kleinsasser) issued Apr. 28, 1987 is disclosed a feeder which provides a shelf above the trough with the hopper discharging onto the shelf in a manner so that the feed remains on the shelf but can be moved from the shelf to the trough by the animal as required. Feeders of this type have achieved significant commercial success. Adjustment of the height of the shelf is necessary for the purpose of accommodating different types of feed and different feed rates and this is obtained by a hand crank screw which operates with a threaded nut to raise and lower a strap carrying the shelf. The screw is used in adjustment of this device because the deposit of the feed onto the self requires an accurate adjustment of the distance between the shelf and the bottom edge of the hopper so that cruder systems with a less fine adjustment have been rejected.
In a number of US patents it is known to provide relatively crude adjustment techniques. For example the following patents provide adjustment devices; U.S. Pat. No. 1,719,245 (Smidley) issued Jul. 2, 1929, U.S. Pat. No. 3,552,360 (Nelson) issued Jan. 5, 1971, U.S. Pat. No. 4,242,985 (Freeborn) issued Jan. 6, 1981, U.S. Pat. No. 4,278,049 (Van Dusseldorp) issued Jul. 14, 1981, U.S. Pat. No. 4,351,274 (Pannier) issued Sep. 28, 1982, U.S. Pat. No. 4,462,338 (Thibault) issued Jul. 31, 1984, U.S. Pat. No. 6,408,787 (Clark) issued Jun. 25, 2002.
It is also known to provide arrangements in which adjustment in a relatively crude manner is effected by selecting one of a plurality of holes in which to locate the pin of an adjustment lever so that the adjustment is effected step by step. As the holes must be necessarily a certain distance apart, such an adjustment provides a relatively crude distance of adjustment so that the fine tuning necessary for determining the specific dimensions of an opening to accurately control the rate of flow of feed material is not possible in such a system. One example is shown in U.S. Pat. No. 6,637,368 (Bondarenko) issued Oct. 28, 2003. This provides a link which extends along one end wall of a feeder and a lever can be moved to place a pin into a selected one of a number of holes in the end wall.
U.S. Pat. No. 5,603,285 of Kleinsasser issued Feb. 18, 1997 of the present assignees discloses a further similar device where additional adjustment of the height of the shelf is possible but again fine adjustment is provided by a screw.
U.S. Pat. No. 5,967,083 also of Kleinsasser issued Oct. 19, 1999 of the present assignees discloses a further similar device where additional adjustment of the height of the shelf is possible by extending the strap using a double flap arrangement which folds up or down as required to extend the length of the strap but again fine adjustment is provided by a screw.
In U.S. Pat. No. 6,923,142 also of Kleinsasser issued Aug. 2, 2005 of the present assignees shows an arrangement which includes a hopper above a shelf onto which feed can fall to be taken by the animal or dropped into a trough below the shelf. The height of the shelf is adjustable to change the width of the opening through which the feed passes to control feed rate. The shelf is carried on straps which extend along the end walls of the hopper and are movable by an adjustment linkage defined by a plate carried on the end wall and a manually adjustable lever mounted for pivotal movement on the plate. The plate has an arcuate outer edge which is serrated to define an arcuate row of saw teeth and the lever is formed by a flat of sheet material which lies in a plane parallel to and slides over the plate and includes a portion thereof which is bent out of a plane of the lever into the plane of the plate which is also serrated with a row of saw teeth shaped to mesh with the saw teeth of the arcuate portion. The portion of the lever is movable in a direction away from the plate a non-meshing position in which the lever is free to move around the pivot axis.
However this arrangement is provided for fine adjustment of the shelf relative to the bottom edge of the hopper over a limited extent so as to control the release of the feed and the larger adjustment for setting the basic height of the shelf is carried out using the folding flap arrangement disclosed in U.S. Pat. No. 5,967,083 above.